[Libav-user] Questions about h264_amf encoder

[Leandro Moreira]

Chao this forum only discusses ffmpeg libav related thing not command line
... but you can do a ffmpeg tutorial
http://slhck.info/ffmpeg-encoding-course/#/

On Sat, Mar 24, 2018 at 5:00 AM Chao Liu <yijinliu at gmail.com> wrote:

> Hi,
> I am trying to see how good h264_amf encoder is. I use ffmpeg to encode a
> 1080 video on Windows 10 running Ryzen 5 2500U. Two observations:
>
> - The encoded video quality is pretty poor, much worse than x264 with a
> smaller bitrate.
>
> - I got about 70fps with ~70% GPU usage. I was expecting to get better
> numbers though.
>   As a comparison, on a much slower intel CPU Celeron n3450, using
> h264_vaapi to encode the same file, I got 30 fps with less than 20% GPU
> usage.
>
> The command I use is:
> ffmpeg -i transcode-test.mkv -pix_fmt nv12 -c:v h264_amf -profile:v
> constrained_baseline -rc cqp -qp_i 0 -qp_p 0 -qp_b 0 h264_amf.mkv
>
> (looks like the qp parameters don't change anything..)
>
> Did I do sth. wrong?
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